In a solder system containing aluminum on one side, as in the case of a CMOS wafer, the problem exists of rapid native oxidation of the aluminum surface—forming an oxide layer that can impede solder bonding generally, and wafer-to-wafer bonding in particular. Common methods used to combat the oxide formation include pre-bond cleaning (plasma, chemical), high force during bonding (breaking the oxide), and gas treatment prior to bonding (forming gas at temperature), all of which add complexity and cost to the bonding operation.